diff --git a/ggml.c b/ggml.c
index 086db96af..3d4f931df 100644
--- a/ggml.c
+++ b/ggml.c
@@ -21360,6 +21360,10 @@ void gguf_set_kv(struct gguf_context * ctx, struct gguf_context * src) {
 void gguf_add_tensor(
              struct gguf_context * ctx,
         const struct ggml_tensor * tensor) {
+    if (gguf_find_tensor(ctx, tensor->name) != -1) {
+        GGML_ASSERT(false && "duplicated tensor name");
+    }
+    
     const int idx = ctx->header.n_tensors;
     ctx->infos = realloc(ctx->infos, (idx + 1)*sizeof(struct gguf_tensor_info));
 
diff --git a/gguf-py/gguf/gguf_writer.py b/gguf-py/gguf/gguf_writer.py
index e3dbca454..ec44ac9f3 100644
--- a/gguf-py/gguf/gguf_writer.py
+++ b/gguf-py/gguf/gguf_writer.py
@@ -63,6 +63,7 @@ class GGUFWriter:
         self.kv_data_count = 0
         self.ti_data = bytearray()
         self.ti_data_count = 0
+        self.ti_names = set()
         self.use_temp_file = use_temp_file
         self.temp_file = None
         self.tensors = []
@@ -197,6 +198,10 @@ class GGUFWriter:
         if self.state is not WriterState.EMPTY:
             raise ValueError(f'Expected output file to be empty, got {self.state}')
 
+        if name in self.ti_names:
+            raise ValueError(f'Duplicated tensor name {name}')
+        self.ti_names.add(name)
+
         encoded_name = name.encode("utf8")
         self.ti_data += self._pack("Q", len(encoded_name))
         self.ti_data += encoded_name